DIY - Home Solar - Partially getting off the Grid More Safely

[hooterman2828]

great setup, wish i had a good battery monitor system my dam wellsee 60amp works great except it don't stop charging when the charge light goes out, my 20amp wellsee seems to work find. anyway i gotta clean and straighten it up a bit. and make an update video.

[rhandsom]

@hooterman2828 Thanks for the comments. My tri-metric 2020 works really well. I don't have any complaints about at the moment. I think a good battery monitor gets to be more critical as your system grows. Take Care.

[NexusRebellion]

Series, not serial. Also, if your 12 volt panels are wired in series you should be putting out more than 12 volts.

[rhandsom]

@NexusRebellion Thanks for you comments. Sorry for the tongue slip, when making these videos, we often get tongued tied etc. Also, 12V panels in series or parallel are still considered 12V panels, even though they are putting out more than 12V. Actually, a single 12V panel puts out between 17v to 19v. My original 2 were in series putting out 36V and were connected to a 12V system, now they are attached to a 24V system. See my channel for my latest videos, this is an older one. Take Care.

[NexusRebellion]

@rhandsom Lol, I figured it was just a slip up. And thanks for the reply!

[free888368]

buddy thanks for your shairng^-^

[rhandsom]

@free888368 Glad to contribute, Take care.

[palletman2]

good video i want to get anothe mppt 250 i have 1 withe 3 hf45wtt kits and 5 batterys ill try to hook both up to my pannels an see if they work togther or will they still amps from each other i have the pannels in series/24 volts an i have hf/chagerhooked up 12 volts split so im thing i can go two mppts

[rhandsom]

@palletman2 Thanks for your comments. Since I have 2 different sets of panels, 1 set = 12v the other = 24v, I had to have dual mppt charge controllers. If your setup is similar, then maybe as long as your charge controllers are connected correctly to your battery bank and they read the same voltage, then they might work in tandem.

[BigAlxr7007]

Really like your system

2 Mppt charge controllers. wired up the manufactures way.Even engineers need help sometimes. Can't go wrong with manufacturing specs.

Everyone has their opinion I guess.

Keep up the great work. Looking for more updates on your system.

Al [ Canada ]

[rhandsom]

@BigAlxr7007 Thanks for the comments. And yes, everyone has their opinions, but overall folks have been helpful. My system has expanded a little since this video. You can check out my latest videos on my channel. Thanks.

[electrodacus]

It was the right decision to get an additional controller since you have different type of solar panels.

As for MPPT vs PWM I will say that usually with the difference in cost you can get larger solar panels for PWM and get the same or better total power.

It was a time when solar panels where more expensive / watt but at current prices for solar panels and MPPT it dose not make much sense.

Also is always better to reduce the power consumption then to increase production.

[rhandsom]

@electrodacus Thanks for the comments. The decision to go with dual charge controllers was based on the manufacturer's recommendations in accordance with my setup. MPPT's are more expensive true, but the performance boost I've personally witnessed is well worth the extra cost. Whether it makes sense or not depends on the designer's requirements. By trade I'm a Systems Engineer, when designing systems I try to design for safety, performance and reliability, so MPPT's fit my requirements.

[electrodacus]

@rhandsom I'm electrical engineer and I was saying that with the difference in cost from PWM to MPPT you can get larger solar panels and the end result as monthly energy generation will be the same or even a bit better also the PWM are more reliable on log therm since are much simpler design no electrolytic capacitor to pop.

Also a good approach is also to reduce the power consumption by using more energy efficient devices it can be cheaper than purchasing more solar panels and batteries.

[rhandsom]

@electrodacus This is a classic difference of opinions between Engineers. I've read the technical datasheets for various PWM and MPPT's and I have to respectfully disagree with your assessment. There is a reason why they cost more, because they give better performance. As an Engineer, you know that product quality has a lot to do with the MTBF. Different brands will not have the same failure rate. I also have a less expensive PWM, but It didn't meet my charging system requirements.

[electrodacus]

@rhandsom I was not talking about quality there are low quality PWM and also low quality MPPT.

They have different construction the MPPt needs a DC-DC converter so it will use coils or transformers and large capacitors and PWM only needs power MOSFET and no coils and large capacitor the later usually having problem because of high temperature inside the controller.

Also my main point was that $ difference can buy more solar panels so you get the same or more out.

Good PWM is Steca. 

[rhandsom]

@electrodacus I can respect your point of view on this, however I must still disagree. There are many factors to consider when designing a system and cost is only one aspect. Also, good panels do not guarantee good performance. Again, there are other things to consider. The MPPT's I use cost $198 a piece from ecodirect, well worth it. That's less than some low watt panels and a little more than some PWMs. Every opinion is valid, yours and mine. I just share what worked for me. Thanks;

[electrodacus]

@rhandsom You already have this great MPPT controllers and with your different solar panels is not a bad choice.

The Steca PR3030 can be had for about 100$ that is 30A so almost 300$ difference.

With 300$ you can get about 100W of solar panels if you consider 3$/Watt this even at 700W is at least 14% more solar panels and MPPT will only in best condition get this over PWM but it will probably be much less.

If you want to get off grid you will need to reduce consumption.

[rhandsom]

@electrodacus I'll take a look at the Steca and compare. Thanks;

[nrodge1]

Looking good. I finally caught up with all your changes. You might want to consider getting a Grid Tie for every day use. Maybe have it so that when the batteries are charged the excess goes to the grid so nothing goes to waste and you can bypass the battery loss and move towards 80% efficiency. I don't know if the MPPT on those controllers will play well with a GTI, you would have to experiment and keep an eye on the system.

[rhandsom]

nrodge1 Thanks for the suggestion, I've wondered about adding a GTI to the system. Do you have any suggestions?

[nrodge1]

rhandsom, Just one of those ebay Power Jack 300W 14V to 28V ones should be enough to cover the excess. They are working good here. Do not connect it to "24V" panels since open circuit they can go to 40V ! I've posted lots of GTI info on the forums at techluck.com , drop on by!

[rhandsom]

@nrodge1 Thanks, I'll check it out.

[randacnam7321]

The controllers should be grounded at the neutral side of the battery bank. Most charge controller load disconnects shut off the load on the neutral side of the load (it has to do with the switching method), and your using the load neutral bypasses this. Also, do not wire the PV array to both charge controllers at once. Connect the new modules to one controller and your existing array to the other controller. Wiring one array to two controllers will cause both to not work properly/fail.

[rhandsom]

@randacnam7321 Thanks for the tips, but these controllers may be a little different from what your used to. Per the manual on page 14 section "3.4 Wiring", these controllers are negative ground controllers, and can be earth grounded on any of the negative terminals. It also says it's recommended but not required. Also, the PV arrays will be separate, the (+) leads come into a 60 Amp single pole 2 circuit switch branching out to separate controllers, I'll update the schematic to show this. Thx